The only difference is that on a wild pitch the blame is attached to the pitcher, and on a passed ball it's put on the catcher.

In reality, it's not that simple. The league leader in passed balls will almost always be the catcher who has to handle the most knuckleballs. The passed balls that occur when R.A. Dickey pitches are less about the catcher than about Dickey's knuckleball -- but the catcher gets the blame.

The Twins this year have had four catchers work at least 100 innings. Joe Mauer has three Gold Gloves on his resume. Ryan Doumit is regarded by the people trying to measure catcher defense as perhaps the worst backstop in the game. Chris Herrmann and Josmil Pinto are rookies, and Pinto in particular is viewed as a raw receiver

Mauer and Doumit have been charged with three passed balls apiece; Herrmann and Pinto none. Add the passed balls into the mix, and Mauer is up to .26 per nine innings, Doumit to .48.

To put this in a larger context, the American League teams have a total average of .37 wild pitches per nine innings. So Mauer is considerably better than the league average, Herrmann a bit better and Doumit and Pinto are worse.